vienna



in allryl-groups.

Patented Feb. 12, 1924,

suites at" liter (ll FlCE.

LEON LILlIllElllfl lElliil], till ALUEE'IBIA.

N 0 Drawing.

1 0 all whom it concern Be it known that T, LEON LILIENFELD, of Podhajce, loland, a citizen of Poland, residing at 1 Zeltgasse, Vienna Vltll, Austria, have invented certain new and useful T1nprovements in and Relating; to the Processes oi Making; lt-lighly-liltherified Ethers of Cellulosic Bodies (for which I have filed patent applications in foreign countries as follows: In Austria, April 1, 1.919, and August (i, 1919; in (lerma y, August 25, 1919, and others later dates), oil which the tollowing is a specification.

(ll: cellulose and its conversion products and derivatives, those alkyl others Which contain. a low number of a l 71 groups, i. e., those in Which. a tow only the hydroxyl hydrogen atoms are replaced by alkyl groups, have the common feature that the field of utility very restricted compared with the field of utility ot the alkyl others or the higher stages of allrylation. The reasons for this lie in the properties that are peculiar to the various allryl-ethers of cellulose poor Thus for example, low ethylatiou and methylation products of cellulose, While soluble ina number of organic solvents, they are also soluble or capable of swelling in cold Water. Conversely, the arallryl ethers, notably the beuzyl-ethers of cellulose, Which are poor in arallryl-groups, While insoluble in water, are also practically insoluble in the important industrial orgranic solvents. The expression cellulosio bodies means cellulose itself, and its conversion products or derivatives; the expression others means allryl and arallryl derivatives, and the expression etherification means allrylation or arallrylation.

The expression to ether-lily, means to alltylate or aralltylate, and the expression etheri't'yingr zitgents means alltylating or arallrylatinnagents.

it is only when the number of alkyl: groups introduced is relatively great, that the alhyl-ethers oi? cellulose possess properties which give them Wide field ot' technical utility, The increase in the number of allryl-groups which etlected by observing,- suitable conditions oi Working, opens up for the ethyl-others and inethylethers ct cellulose, not only an extraordinary increase in the series oil organic solvents in Which they may be dissolved, but also causes their solubility or capacity to swell in Water to dis- Application tiled January 1c, 1921.

Serial No. aaaaao.

appear. In the case oi the benzyl-ethers of cellulose, as Well as of its conversion products and derivatives, the increase in the number of benzyl-groups procures an excel lent degree oi": solubility in organic solvents.

The manufacture of alkyl-ethers 0t cellu lose which are insoluble in cold Water, and especially those that do not svvell in cold Water, but are soluble in a sufliciently large number of volatile solvents, Was possible hitherto only When the alkylation tool; place in the presence of a large excess of alkali, either calculated on the amount of cellulose or on the amount of alkylating agents or on both. (cc torinstance U. S; Patent 1,188,- 376.)

To illustrate the above statement, if alkalicellulose be taken as the starting material, then the latter had tobe treated. With very large excesses of alkali in order to obtain alkyl-celluloses having the properties required for technical use, (See for instance U. 55. Patent No. 1,183,376, Exam ple Kl.) If according to Example VIII of said patent there "were taken as the primary material the conversion products or derivatives of cellulose Which are soluble in alkalies and have many advantages for the alltylation of cellulose and the operations Were therefore effected in alkaline solution, then for the two-stage Workinn; given in the said example, it Would be necessary to treat the reaction. masses (produced in the first alkylation stage, and containing; allrylmelluloses oil a lower degree of allrylation) with considerable excesses of allrali and alkylating; agents in order to pro duce allryl-celluloscs which are soluble in a suftlciently large number of organic solvents and-in so far as ethyl and methyl celluloses are concerned are further insoluble in cold Water, or are resistant to cold Water.

This technically desirable result is not attained by operating in the manner usually employed in allrylating; other alcohols1 With quantities ol? alkali which are calculated on the alcohol or on the alltylatinp; agents or on both or With quantities 0t alkali that do not exceed; the theoretical quantities, by any considerable extent.

If for instance the allralisolublederiva tives or conversion products of cellulose are employed as starting materiahand if as in the Examples VTTT, Vlll or similar examples of ll. El. Patent 1,188,376, even very,

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large excesses of ethylating agents be used, but at the same time only quantities of alkali are introduced which are calculated on these ethylating agents or do not considerably exceed the calculated amounts, and which therefore when calculated on the cellulose, still show a very large excess,then ethyl-celluloses of a higher degree of ethylation will be produced Which are insoluble even in cold wa ter and are soluble in a number of organic solvents, but which, however, are'not sufficiently permanent against cold water either in their flocculent or pulverulent original conditioner in the form of products made therefrom, such as films and the like. If for instance a film made from an ethylcellulose of this kind be subjected to the action of very cold water, for instance at 1 C., then this film/will swell up, will become jellified, slippery and crumbly. If the amount of alkali be increased by a not very considerable amount then the film made from the corresponding cellulose-ethylether will withstand ice-cold water much better. In fact it certainly does not become jellified and also not crumbly, but it shows in ice-cold Water still an appreciable degree of extensibility. Only when the percentage of alkali of the reaction mixtures has been increased to quite an extraordinary degree, can there be obtained according to the examples VIII, VII, etc., of Patent No. 1,188,376, ethyl-celluloses which have perfeet resistance even against ice eold water,

Q and which ethers. further are soluble in the large number of organic solvents so important in the industries.

If for instance benzylation is effected according to the methods stated for the ethylation in the Examples VIII, VII, etc., of said patent, then again considerable excesses of alkali must be employed in order to produce. benzyl-celluloses which possess the desired degree of solubility in a number of solvents suflieiently large for industrial purposes.

If alkali-cellulose be chosen as the starting material, then considerable excesses of alkali calculated on the cellulose must be used if the intention is to produce alkylcelluloses that are free from the above described disadvantages, namely, solubility in cold water or insuflicient' resistance to cold water or insufiicient solubility in organic solvents. Likewise, if aralkyl ethers of cellulose are desired, having a sufficient solubility in organic solvents, then also consid erable excesses of alkali must be used, when using alkali cellulose as the starting material.

Operating with large excesses of alkali is, however, accompanied by very considerable objection. First it increases the cost of working considerably due to the cost of the excessive quantities of chemicals used.

There is also the important :fact that large excesses of alkali decompose any excesses of alkylating agents or aralkylating agents thatmay be employed, especially in a heated state, so that the latter cannot be recovered as such by distillation, separation, etc. In any case, with the introduction oi? large excesses of alkali, the systematic recovery of any excesses of alkylating agents or of aralkylating agents which may be employed (and when di-alkyl-sulphates are used, the systematic recovery of the second alkyl' groups that have not come into reaction) is either not possible or they can only be recovered in the form of alcohols or ethers. Moreover, a recovery of the alkalics used in excess seems to be practically impossible. There is further the serious disadvantage that so long as the ethers of the higher degrees of alkylation or aralkylation are not formed, extreme care must be taken with the addition of alkali and the temperatures when large excesses of alkali are used. The ethers of cellulose, of lower degrees of etherification are very sensitive to alkali-hydro ides, especially in a heated state, owing to the free hydroxyl-groups contained in them. Certainly the alkyl groups or aralkyb groups that have been introduced are not split off by the action of alkalies under the action of heat; but the non-alkylated or nonaralkylated part of the molecule is liable to undergo a change, probably in the sense of splitting (i. e., depolymeriaation). This is shown by the fact that products produced from cellulose ethers which have been treated in the intermediate form of the ethers of a lower degree of etherification with considerable quantities of alkali-hydroxides under the action of heat, have not by far the advantageous properties which are possessed by the ethers of cellulose which have not been attacked in heat by alkalihydroxides during the etherification. This circunistance diminished considerably the reliability and uniformity of the etherification pro esses hitherto employed.

The discovery of a process which enables the alkylation or aralkylation oi? cellulose with the calculated quantities (or not very considerable excesses) of alkali, has been an extremely important technical desidcratuni.

The surprising discovery has now been made that ethers of cellulose of lower de grees of etherification, (that is to say, for instance, the water-soluble or cold water sensitive ethyl or methyl-ethers of cellulose or the insoluble or difiicultly soluble benzyl-ethers of cellulose) can be converted into ethers of higher degrees of ethcrification in the presence of quantities of alkali which can be regarded as moderate compared. with the quantities hitherto required. by removing the water wholly or partially from the reaction mixtures containing the ethers of Ill) till

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the lower degrees oil" etherification before the further etherification, and effecting the further etherification with the exclusion of Water or in the presence of only moderate quantities of Water, i. e., an amount of Wator not substantially exceeding 6.83 times the Weight of the cellulose used as primary material or that amount used in the prepa ration of the primary material. under etheri flo ation.

The improved. process of this invention thus renders possible amongst other things, the conversion of cellulose others (including the allryl'cthers) bit lower degrees of etherilication (allrylzition) into (alkyl)ethers of higher d k ot ctherilication (allrylation) by means of quantities ot alkali which are calcul. ed for the amounts of the etherittyino; (allrylaungr) employed or which do not considerably lesceed such amounts.

lit to be understood that the amounts of illl'illli required for the further letherilication (allrylation) may be incorporated With the reaction mixtures also hetore the water is driven off. lln such a case care must be on that the allralies do not damage the llryl)-cthcre of lower degrees etherilication (allcylation). lit the operation is carried out in dis sense according to the pre ent invention with only small. excesses ct alkali. then in spite oil the incorporation of the alkalics before the "Water is driven oil", there will always be produced useful (allryliethers of higher degrees of etheriticati on (allrylation) it has further been discovered that the present process brings with it also a con siderable technical advantage When instead oitoi ieratinrr With small, that is to say for instance calculated quantities of alkali. or incmisiderable excesses of allrali, operations are made With. considerable excesses of alkali. lin such a case the present process es rise to the: technical advantage that technically. perfect (a;llcyl)ethers of a hi .grher decree of etherilication (allrylation) can be obtained with smaller qiiantities of etherifyinp; (allrylating) agents than when working in the presence of Water in excess oil? the amounts herein prescribed. The products obtained in this manner can be treed much better and in a much shorter time from the reaction lay-products by hing .rith Water. and the yields arebeti when working in the presence ct amounts oil. water. what has been said, the ideainight be termed that the dehydration of the primary materials or their solutions, and the efi ectingg of the entire alkylation beginning with the treatment of the primary materials. in. absence of Water or in the presence of small quantities of Water, might be elleeter".

Eiuch a process however meets either inter CPI

ectares surmountable dilliculties or difiiculties which are so great to render the process prae tically impossible.

For instance it is practically impossible by driving out the Water to tree from Water the alkaline solutions ot the allrali-soluble cellulose derivatives and conversion prod ucts. They soon change in a manner which is highly disrulvantanccus for the subsequent alhylation or arallrylation. they precipitate either in the form of a jelly or as curds andthen they can no longer be sati tactorily a l'ylated or arallrylatcd.

The drying oil the alkali compounds of the cellulose, meets with, great dilitlculties. The removal out the We at room temperaturc is ertremely troublesome and time taking. Even under reduced pressure and with the use of lrneadiun; devices, a dehydration of thislrind tCtlIGS a considerable length of time. lit the temperature is raised then there is a risk oi depolymeriaing; the cellulose by the alkali. .tltS a matter of tact, alli'ali compounds of. cellulose, which have been provided with the necessary quantities or alkali tor the Whole allrylation process. experience a considerable alteration when they are dried in the air or in a vacuum with the use of heat. They are converted into dcpolynieriration products Whose others in the form o'l. technical. articles are by tar interior to the corresponding; others ot cellulose which has not been so changed. The tediousness ot the dryi process and the ei ttent of the depolyineriring action ol the allralies are in direct ratio to the quan tity of the allrali contained in the alkalicompounds and the drying temperature The circumstances are however quite dih terent when an ether of a lower degree oil. etlieriiication has been. tor-med. This ether withstands the action cit heat and can therefore be :treed trorn i ater easily and ouiclrly Without sufteringr any change in its chemical or physical. properties. l t is to be noted that there is. in such a case no considerable amount ot tree alkali. present.

As indicated above the process also has advantages in the further etheritication (all ylation or arellrylation) of cellulose others oil? low dent]. e of: etheriticotion. which have been produced either irrozn allzali cellulose or troin other cellulose derivatives Whether soluble or insoluble 'n allrali.

The process will now be described more fully with reference to also.) soluble cellulose oonversion products or derivatives as starting materials.

As alkali-soluble conversion products or derivatives there may be employed amongst other su ances, raw or purified viscose oil any de rot reversion (toinstance a solution of celluloserant. '611tb@ or the like produced according to the process described. in

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lltllli llllll Patent No. 1,379,351, further alkali-soluble cellulose-hydrates (acid-cellulose and the like), such as are obtained by the treatment of all kinds of cellulose with hot solution of caustic alkali or Schweizers re-agent; fur ther, the alkali-soluble hydro-celluloses (Flechsigs amyloid, Ekstrtims acid-cellulose, Guignet-cellulose and the like) which are obtained by treating cellulose with strong mineral acids and water-precipitation; the

I cellulose depolyinerization products such as are obtained by treating cellulose with zinchaloids separately or together with acids, and subsequent precipitation; further, the alkali-soluble conversion products which are produced by the action of saponifying agents upon cellulose-esters; the cellulose-hydrates produced by extensive heating of viscose according to German Patent No. 155,745; and artificial silk waste, etc.

For the purpose of carrying out the process, an alkali-soluble cellulose derivative or conversion product is dissolved in aqueous alkali, mixed with the corresponding alkylating agent, and heated until reaction ceases, that is to say, until the formation of an alkylcellulose of a lower degree of alkylation, for instance a water-soluble alkyl-cellulose. The addition of the alkylating agents may take place either at once before heating or drop by drop or in small portions during the heating.

After the complete conversion of the cellulose, or the corresponding cellulose derivative or conversion product into the water soluble alkyl-ether of a lower degree of alkylation, the water is driven off from the reaction mixture; this may be done either under atmospheric or reduced pressure. By heating, the complete or partial dehydration of the reaction mixture is assisted. Obviously, Working in vacuo allows lower temperatures than working under atmospheric pressure. Energetic stirring or kneading facilitates the dehydration. Under atmospheric pressure it is sufiicient to employ temperatures between &0 and 100 C., whereas in vacuo the temperature may be as low as (3., or it may even drop to room temperature.

According to the quantity of the water driven off, either a dense cheesy pasty mass or a substance that is dry to the touch and is readily rubbed to powder is obtained. This latter product would not contain substantially over 20% of moisture. If the mass has been energetically stirred or kneaded during the driving off of the water, then there remains a more or less finely divided, fairly fine or granular powder, according to the amount of water driven oil". If through insufficient stirring this is not the case, then it is advisable before further treating the residue to convert the said residue by rubbing, grinding, crushing or the like, into a finely divided condition. In

order to produce the finest possible subdivision the powdered residue can also be passed through a sieve. It is of course understood that I do not restrict myself to this degree of removal of moisture.

The residue is then mixed preferably by stirring, kneading or the like, with an alkali for instance an alkali-hydroxide either in the solid form or in a very highly concentrated aqueous or alcoholic solution (t0 to solutions being mentioned by way of example). The addition of the alkali may be effected either at once or in small portions. A too great rise of temperature during the addition of the alkali is preferably to be avoided. Then the alkylating agent is added. and the mixture heated until the desired. final product, that is to say, an alkylcellulose of a higher degree of alkylation which is insoluble in water, non-sensitive to water, and readily soluble in organic solvents, has been produced. The alkylating agent is added either before heating, in one portion, or is added during the heating in a number of portions or drop by drop or in the form of a slow stream.

The alkylation in the first stage, that is to say, in the manufacture of alkyl-cellulose of a lower degree of alkylation, and in the second stage, that is to say, in converting the cellulose ether of a lower degree of alkylation into an ether of a higher degree of alkylation, may be efi'ected according to the nature of the alkylating agent, either at atmospheric pressure in vessels provided with reflux condensers or in pressure vessels (bombtubes, digesters or the like). It is advisable to stir or knead during the alkylation process. Any volatile byproducts of the reaction, such as alcohols, ethers and the like, may be distilled off either during the alkylation or after the alkylation is completed.

The isolation of the finished final product from the reaction mixture is effected for instance by collecting, after previous addition of water, the final product upon a filtering device (filter, filter press. centrifugal ma chine, rotating filter and the like). thoroughly washing the said product with cold or hot water, and drying the same. If desired, the reaction mixture mixed with water may be acidulated before filtering, or the washed alkyl-ether of the cellulose may be treated with a dilute acid and again washed before drying.

As above stated, the quantity of alkali necessary for the second stage may be added, not after but before the expulsion of the water, to the reaction mixture containing the alkyl-cellulose of a lower degree of alkylation.

It is obvious that the process may also be carried out by isolating the alkyl-celluloses of lower degrees of alkylation. that is to say, for instance, the water-soluble ethyl-celluloses or the insoluble or ditlicultly soluble heneylcelluloses acd' the lilre dirointhe reaction mixture, freeing the same completely or partlyftrom any adhering Water, andthen lurther etherilying them.

The isolation of the cellulose-others of lower degrees ofallrylation may be ettected either by boiling" and ashing With hot Water (the Water-soluhle *l-cellulosc for instance are usually soluble only in cold Water, and ar but slightly soluble or not at (all soluble in hot Water) or in the case or allrylcelluloscs of lower degrees of allrylation which are insoluble in organic solvents, by precipitating with a suitable precipitant, tor instance alcohol, or a mixture of alcohol and ether, or acetone or the lilre.

its alkylating agents allryl-ethers of inorgarlic acids such as the allryl-haloids, the allryl-sulphates, the alkyl-phosphates, and the like may he employed.

l have aboye referred more particularly-to the production of the alkyl others of low degree of alkylatio-n and the further alkylation thereof, The arallcyl ethers (e. g., the henzyl ether mentioned) will he prepared in a closely analogous manner, but as above noted, the mode r purifying the arakyl others "will, as alcove noted, he ditlerent,due to the different soluloilities thereof.

Example.

lose-derivative or conversion product, for instance oi the cellulose iranthorgenate described in Patent No. 1,379,351 or of a visc ose purified by an olderprocess, for instance liy salts or salts andacids, alcohols or other precipitating agents, or a cellulose hydrate, produced by treating cellulose With a hot solution of caustic allrali or with lf lchweizers reagent, and subsequent precipitation or of the cellulose hydrate produced by heat-ins; from viscose according to the process descrihed in German Patent lli'. d or a hydro-cellulose, ainyloi chacid {Minuet-cellulose and the like produced by treatment oi cellulose rrith strong sulphuric acid, or 0T another ccllulose hydrate or the like containing about 5200' parts lay Weight of cellulose employed as a startino; material and ahout 200 parts by Weight 0' caustic soda, are gently heated, and mi ror try I oi di-ethyl sulphate. The addition ,alres one to two hours, then it necessary the mixture is subsequently heated on the raster bath.

The temperatures are for instance as follows \ he reduced to about 30 or 4:0. gradually with SGO ZQO parts Temperature after minutes, 18 0.

Temperature after minutes, 21 C.

Tempe ature after 4:5 minutes, 2 1- G.

Temperature after 1 hour, 27 C.

Tenperature after 1 hour 15 ninutes, 30 s Tecmperature after 1 hour 30 minutes, 33

Temperature after 1 hourzdli minutes, 37 C,

Temperature after 2 hours, 11" C.

(Now the "Whole of the direthylsulphate has goeen incorporated in the reaction mixture Temperature after 2 hours 15 minutes, ar C.

Temperature after 2 hours 47 C.

Temperature after 2 hours, 48 o.

Temperature after 3 hours, 51

Temperature after 81 hours 15 minutes,

30 minutes,

minutes,

Temperature after 3 hours 30 minutes,

contains besides the loy-products, the ethyl ether of cellulose ivhich is soluble in cold Water. Thls maybe TGCOQ'lllZQCl for instance loy the fact that the Watery solution oi a sample taken from it-in contradistinction to the primary solution gives no precipitate with sulphuric acid, and further loy the fact that a sample taken from it is soluble in glacial. acetic acid. The reaction nurture is new preterably allowed to cool, it necessary, attorbeing filtered and is heated either in an open vessel (evaporating dish or the like), or in vacuo (for instance in a vacuum kneading machine or the like) for the purposeof driring out the water, preteraloly being stirred or kneaded continuously.

its the temperature need not exceed 100 it s suffic ent to use hot Water or steam as a source of heat. it the Water 153 expelled by heating; under atmospheric pressure, it

is preferable to use a temperature which is not lOBlOW 40 C. It is however admissible to go up to 90-100 C. It the evaporation is carried out in vacuo the temperature may or course the required expulsion ct Water can be ohtained more easily when active stirring, or kneading is employed, both under atmospheric pressure or in vacuo even WitllOlll; heating, more particularlyvvhen thin layers are treated or When energetic agitating orlrneading is employed, but a correspondingly longer time is required. 1

The expulsion oil Water is continued until i the reaction mixture has reached a Weight of 500-1400 parts by Weight (accordlng to ill) "to or beyond 500 parts by weight).

.washed with hot or cold water. residue may however be treated with a dithe degree of removal of water required and according to the quantity of di-ethyl sulphate used).

The figures 500 to 1400 parts correspond to ratios respectively of about 5:1 and 6.83:1, of water to actual cellulose in the material being operated upon. The evaporation is preferably continued sufficiently to bring the existing ratio down to below 6.83 :1.

The resultant parts or the friable body which is dry to the touch is disintegrated if necessary, or rubbed down, and if necessary passed through a sieve, whereupon (and preferably after cooling) to 150 parts by Weight of powdered caustic soda or the equivalent quantity of caustic potash, the temperature being preferably reduced, are added in small portions while it is rubbed, stirred or kneaded. (If it is only intended to reduce the quantity of the alkylating agent to obtain a quick filtration or washing of the final product, the quantity of added caustic soda can be increasedrilip 1e resultant mixture which is usually in powder form is then mixed either in an open vessel or in a closed vessel with 300800 parts by weight of di-ethyl sulphate in one or several portions and is heated, being preferably at thesame time stirred or kneaded. A steam or water bath is a sufficient source of heat. The reaction proceeds at temperatures which lie between 50 and C. and is usually completed after 13 hours. To make quite sure, the heating can be continued for another 12 hours. Any alcohol or ether that may have been formed. as a by-product during the reaction can be dis tilled off during or after the reaction. The final reaction product is mixed with or added to water and optionally after previous neutralization or acidification, is filtered. The filtered residue is then thoroughly The washed lute acid, again filtered, thoroughly washed, and then dried. The drying can be effected either in vacuo or in the presence of air and either in the cold or under the action of heat.

The first filtrates contain the sodium ethyl sulphate which has been obtained from the ethyl sulphate. If quantities of caustic soda were worked with, which were only calculated for the ethyl sulphate, or only with a small surplus, the filtrates can be evaporated, preferably in vacuo, leaving the sodium,ethyl sulphate.

If the alkaline solution of a conversion product or derivative soluble in alkali is not to be ethylated but benzylated, the mode of operation maybe derived from the example given above. It should only be remembered that the product of the first alkylation step, that is, the lower benzyl cellulose is not watersoluble, hence there is obtained as the final product of the first benzylating stage, not a solution of water-soluble cellulose ether but a flocculent or granular paste which is more or less dry to the touch. A sample is not noticeably soluble either in water or in glacial acetic acid or the like. In View of the different nature of the products of reaction, the reaction mixture obtained from the second benzylating step must be subjected for isolating the benzyl ether to a somewhat different treatment from the reaction mixture obtained by etheylating. In order to remove any surplus of benzyl chloride and the byproducts of reaction (benzyl alcohol, benzylether, benzaldehyde or the like), the final product must either be steam distilled optionally under reduced pressure while being kneaded, or be treated with solvents in which the benzyl ether of a higher degree of alkylation is insoluble, while the reaction by-products are soluble therein. This includes for instance ethyl alcohol and other aliphatic alcohols and the like.

The mode of working with alkali cellulose and other alkylating agents, for instance alkyl halides, follows from what has been said above. Of course when using alkyl halides of low boiling point, for instance ethyl chloride and the like, both alkylation stages will be carried out in pressure vessels, preferably while stirring and only the removable water from the reaction mixtures of the first stage obtained from the alkyl celluloses of a low degree of alkylati0n,will be effected either at atmospheric or reduced pressure.

)Vhile above, in the specific description, I have referred especially to the conversion of water-soluble alkyl ethers of cellulose into more highly esterified ethers which are insoluble in water, it is to be understood that the invention embraces the further etherification of any partially etheriied cellulose (as well as partially etherified conversion products and derivatives of cellu lose) into more completely etherified derivatlves.

What I claim as my invention and desire to secure by Letters Patent is 1. A process of manufacturing ethers of cellulosic bodies by converting ethers of cel lulose bodies of lower degrees of etherification into ethers of higher degrees of ethcri fication, which process comprises conducting the further etherification of the ethers of lower degrees of etherification in the presence of an amount of water not substantially exceeding 6.83 times the weight of the cellulose under etherification.

2. A process of manufacturing ethers of cellulose bodies by converting ethers of lower degrees of etherification into ethers of higher (iii iili

ri l-eases degrees of etherification, which process comprises conducting the further etherification of the others of lower degrees of otheri fication in the presence of an amount of wa tor not substantially above five times the weight of the cellulose under etherilicatioin 8. A process or manufacturing others of cellulosic bodies by converting such others or lower degrees of etherification into others of higher degrees of etherilication, which process comprises conducting; the lur thor etl'ieriiication of the others oil lower do groes of otheriiication in the presence oian amount oi water not substantially above 6.83 times the weight oi the cellulose used in the preparation of the primary material under EiJhMlfiCitillOlL 4-. Process oi? manufacturing others of cellusosic bodies by converting such others or lower degrees of etherilication into others of higher degrees of etherilication which process comprises first expell ng water from the reaction mixtures containing the others of lower degrees of etheriiication to such an extent that the reaction mixture contains an amount of water not substantially in excess of 6.88 times the weight of the cellulose under etherification, and then performing the further etherification.

5. Process of inanutacturing others of collulosic bodies by converting such others of lower degrees of otherification into others of hi gher degrees or etherification which proccomprises first expelling water from the reaction mixtures containing the others of lower degrees of otheritication to such an extent that the reaction mixture contains an amount of water not substantially more than 6.88 times the weight oi the cellulose used in the preparation of the primary material unuor otherification, and then performing the further otheritication.

6. A process of manufacturing others of collulosic bodies by converting such others of lower degrees of otherilication into others of higher degrees of etherilication which process comprises first isolating the others of lower degrees of otheriiication from the reaction mixtures, and then further etherii y ing those others in the presence 01E an amount of water not substantially over 6183 times the weight oi the cellulose under cthoriification,

'l. Process of inanui?acturing others of collulosic bodies by converting such others of lower degrees of ethoritication into others of higher degrees cit etheritication. which proc ess comprises first solatinp; the others oi? lower degries of etheriiication trom the re action niiatl'iuros and then eturther etheriiyinp; these others in the presence of an amount of water not substantially ever live times the weight oil the cellulose used in the preparation ot the primary material under othorificationu 8. Process of manufacturing others of col lulosic bodies by converting such others ol lower degrees oil ethcrillcation into etl ers oi? higher degrees Oil otherilication which procoss comprises pe iorninig the it" tllGl etheritication or": the others oi lower degrees of ethorification with caustic allrali and an ester of an inorganic saith the amount of water present in the reaction. mixture being between about five times and about times the weight ol the cellulose under ctheri ticati on.

llroccss oi inzuiuilacturing others of col. lulosic bodies by converting; such others of lower degrees of othcrilication into others of higher degrees of etherification which process comprises performing the :ifurther etheri- .iication oi the others I lower degrees of ethcrilication with. caustic alkali and an ester of an. inorganic acid, the amount oi. water present in the reaction mixture being not substantially in OBIUOI-SS o'lf five times the weight of the co. llose under etherilication.

l0. Process oi. inanuiifactluring others of cellulosio bodies by converting such others of lower degrees of ethc 'lication into others of l'iigher dot s i ethoriiioation which proc ass comprises peribrming the further othoriiication ot the others of lower dcpgi. es of othcriiication with. caustic alkali in. the ljorin of a soluti on oil not sidastantially below 410% strengtlu and an ester (ii an. inorganic acid the amount cit water pres-put in the reaction mixture being not substantially over 6.83 times the weight ot" the cellulose under otherilication.

11. It. process of manuliacturior; others of cellulosic bodies by converting suchv of lower degrees of otherilication into others ol. higher degrees oi? otherilicatio'u which process coinpi" i. perlorniin the further etheriiieation of the others lower degrees of othoriiication with caustic aileili. in concentrated solution. of at least lO'Ya strengtln and an ester oi an inorg inic acid the amount oi we or present in the roacti mirrture not ezrctedingjg about live times weight of the cellulose.

12. fit process oi? manu'i zmturii others of cellulosic bodies by converting; such others of lower degrees oi etheritic: ion into others of higher degrees ot etheritication which process compri is first selling; enter from the reaction in lUPi-i contaii'iing the others out lower degr oi? etheriiicution to such an extent that the reaction. n re contains an amount of water not si iutially ore ceeding; 6.83 tin'ics the wei t oi. the cellulose under otheritication... and then poriliori inn the "further ethorilication with caustic alkali in a concentrated state and an ester oft an inorganic acid,

13. ll process oil manure rring QbllBlS oi cellulosic bodies ui ertinp: such others oi? lower titfl'l'GOS or o 'itication into others cit higher degrees of ethoritication which "ill till

llill lflfi process comprises first expelling water from the reaction mixtures containing the ethers of lower degrees of etherification to such an extent that the reaction mixture contains an amount of water not substantially exceeding five times the weight of the cellulose, and then performing the further etherification with caustic alkali at least a part of which exists in the solid state and an ester of an inorganic acid.

14. A process of manufacturing ethers of cellulosic bodies by converting such ethers of lower degrees of etherification into ethers of higher degrees of etherification which process comprises first expelling water from the reaction mixtures containing the ethers of lower degrees of etherification to such an extent that the reaction mixture contains an amount of water not substantially over 6.83 times the weight of the cellulose under etherification, and then performing the further etherification with caustic alkali, a part at least of which exists in the form of a concentrated solution, and an ester of an inorganic acid.

15. A process of manufacturing ethers of cellulosi bodies by converting such ethers of lower degrees of etherification into ethers of higher degrees of etherification which process comprises first expelling water from the reaction mixtures containing the ethers of lower degrees of etherification to such an extent that the reaction mixture contains an amount of water not substantially over five times the weight of the cellulose under etherification, and then performing the further etherification with caustic alkali at least a partof which exists in concentrated solution and an ester of an inorganic acid.

16. A process of manufacturing ethers of cellulosic bodies by converting such ethers of lower degrees of etherification into ethers of higher degrees of etherification, which process comprises first mixing a material containing a partially etherified cellulosic body with an amount of alkali exceeding in weight the amount of water present in the mixture and then performing the further etherification.

17. A process of manufacturing ethers of cellulosic bodies by converting such ethers of lower degrees of etherification into ethers of higher degrees of etherification, which process comprises first mixing a reaction mixture containing a partially etherified cellulosic body with an amount of alkali exceeding in weight the amount of water present in the mixture and then performing the further et-herification.

18. A process of converting a cellulose ether of a low degree of etherification into an ether of higher degree of etherification, which comprises removing at least a substantial part of the water from the reaction product of the low-etherification process,

and then further etherifying the low etherification product, by reaction with an alkali and an etherifying agent.

19. In the production of ethers of cellulose, the step of evaporating away the water of a reaction product containing an ether of cellulose of low degree of etherification, at least until a dense cheesy pasty mass is pro duced.

20. In the production of ethers of ccllulose, the step of evaporating away the water of a reaction product containing an ether of cellulose of low degree of etherification until a substance that is dry to the touch and readily rubbed to a powder, is produced.

21. The process of alkylating a cellulosic material containing unetherified hydroxyl groups which comprises the step of subjecu ing said material, while mixed with alkali in excess of the amount required by the said hydroxyl groups and mixed with water, the amount of said water being less than the weight of the alkali, to the action of an etherifying agent.

22. A process of producing highly etheritied ethers of cellulose, which comprises reacting with an etheritying agent upon the ethers of low degree of etherification in the absence of sufficient water to make the mass freely liquid at room temperature whereby the amount of etherifying agent to be employed is low.

23. A process of forming highly etherified ethers of cellulosic bodies which comprises adding to a cellulose ether of low degree of etherification, while in a state of dryness at least as great as that corresponding to a dense cheesy pasty mass, a caustic alkali in substantially a solid state, and adding an etherifying agent thereto.

24. A process of forming highly ethcrified ethers of cellulosic bodies which comprises adding to amass of a cellulosic material, all of which has been converted into ethers of: low degree of etherificatien, while in a state of dryness at least as great as that corresponding to a dense cheesy pasty mass, a caustic alkali in substantially a solid state, and adding an etherifying agent thereto.

25. A process for the manufacture of alkyl derivatives of cellulose by converting their alkyl derivatives of lower degrees of alkylation into alkyl der' *atives of higher degrees of alkylation, which comprises subjecting the alkyl derivatives of lower degrees of alkylation to further alkylation in the absence of more water than is necessary to form a pasty mass of the consistency of firm cheese.

26. Process of manufacturing ethers of cellulosic bodies by converting such ethers of lower degrees of etherification into ethers of higher degrees of etherification which process comprises adding caustic alkali to a reaction mass containing a cellulosic ether of a low degree of etherification to form a mixture containing an amount of water not substantiallv above 6.83 times the weight of the cellulose under etherification, and treating the thus obtained mass with an ester of an inorganic acid.

27. Process of manufacturing ethers of cellulosic bodies by converting such ethers of lower degrees of etherification into ethers of higher degrees of etherification which process comprises adding caustic alkali to a reaction mass containing a cellulosic ether of a lower degree of etherifioation to form a mixture containing an amount of water not substantially in excess of five times the 15 weight of the cellulose under etherification and treating the thus obtained mass with an ester of an inorganic acid.

In testimony whereof I have signed my name to this specification in the presence of 20 two subscribing witnesses.

LEON LILIENFELD. Witnesses HERMANN WIMDERLICH, FRANZ SOHIDENSKY. 

